System for controlling the humidity and temperature of air.



I W H. CARRIER. SYSTEM FOR CONTROLLING THE HUMIDITY AND TEMPERATURE OF AIR.

. APPLICATION FILED APR.1908 RENEWED OUT.9,1912.

1 1 01,784, Patented June 30, 1914.

2 SHEETS-$11115! 1.

W12 n asses:

W. H. CARRIER.

SYSTEM EoE CONTROLLING THE HUMIDITY AND TEMPERATURE APPLICATION FILED APR. 23, 1908. RENEWED OCT. 9, 1912.

1 11,784 Patented June 30, 1914.

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UNTTET) STATES PA .nnir ora ion wrtrrs' n. oanarnr, or serrate, new roan, 'assrenon 'ro nnrrnrio irons-n COMPANY, or EUYEIFALO. new roan.

SYSTEM FOR CONTROLLING THE HUMIDITY AND TEMPERATURE OIBAIR.

Specification of Letters Patent.

-lPautented June 3(1 Malia Application filed April 23, 19%, Serial No. @2836). Renewed October 9, 1912. Serial No. 2(24354.

To all whom it may concern Be it known that I, WILLIS H. CARRIER, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and useful Improvement in Systems for Controlling the Humidity and Temperature of Air, of which the following is a specification.

This invention relates more particularly to systems for controlling the humidity and temperature of air in buildings and estalr lishments where it is desirable or essential to maintain auniform humidity and nearly uniform temperature of the air all the year around, or to regulate the'conditions of humidity and temperature in different rooms as necessary by reason of the conditions prevailing in such rooms which have diiferent elfects on the atmosphere therein.

The object of the invention is to produce a practical and economical system which will automatically maintain a desired absolute humidity and nearly uniform "desired temperature of the air in a room or building, notwithstanding great changes of. humidity and temperature in the external atmosphere, and by which also the temperature and relativehumidity in different rooms can be automatically regulated as required for each room.- V I This invention is in the nature of, improvements in the system for heating and humidifying air disclosed in U. S: Patent No. 854,270, granted to me May 21, 1907, in which the absolute humidity of air supplied to the room or building is automatically.

regulated. The patented system is only intended to operate for normal changes of temperature in the external atmosphere be tween predetermined degrees.

The present system embodies two mpon. tant fea-turesz'The first consists of means wherebythe absolute humidity and tempera ture of saturated air is secured and main 'taineo at a fixed poin'tregardless' of variations in external ,atm0spher1c. COIldltlOIlS above or'below a. prevailing point. The second feature consists of means whereby the temperature and relative humidity in each of .severalyrooms are eonjointly and interdependently controlled and the relativeliumidity is maintained at any desireddegree regardless of the effect produced by radiation, infil'tration of cold dry airor of warm moist air, or of moisture evaporation 'or' moisture absorption occurring in the room. The first condition is secured by saturating air at a predetermined temperature with water spray in a humidifier, which is accomplished byheating or refrigerating means controlled automatically by a thermostat whose action is dependent upon the temperature of the saturated-air. W hen the temperature of the spray water is at or. above the, temperature maintained by the thermostat, moisture is added to the air by evaporation to the point of saturation, the'heat of evaporation being derived either from the water, or from the air, or from both conjointly, When the Water is cooled below this temperature by refrigeration, moistureis condensed from the air and is separated therefrom by contact with the particles of water and by an eliminator, so that'saturated air free from entrained moisture is obtained at the desired predetermined temto refrigerator or refrigerator to heater, aceordingly as external atmospheric conditions may demand, so that the two processes do not conflict, oneneutralizing the eflect' of the other. The essential principle employed physical fact that when the water is neither through the humidifier becomes saturated at the wet bulb temperature of the air entering the humidifier; therefore, it follows that whenever the outside wet bulb temperature is belowthe temperature maintained at -the humidifier the water must be heated, and whenever the outside wet bulbtemperature is above the temperature at the-humidifier the water must be'refrigerated. The means for conjointly "regulating the temperature are controlled by a differential wet tube hygriostat which is placed in each of therooms. This hygrostatf; instead of controlling the amount ofm'oisture admitted to the rooms as in the ordinary' methods,' controls instead the dry bulb temperature of the room, so thatthe dryrbulb temperature bears a constant relation to the wet bulb. temperature of saidroom, preferably, but/not necessarily, by regulating the temperature of the humidified air supplied to'theroom. This'revlation is established by the mechanism of in securing theautomatic transfer. from refrigerating to heating depends upon the heated .nor' refrigerated the air passing perature. A. wet tube thermostat is also enaployed for shifting the control from heater and relative humidity in the several rooms ditions cannot be entirely overcome and itis necessary that constant relative humidity be obtained, it becomes desirable toadopt the control as described above, which varies the temperature slightly to maintai.n.absolutely constant relative humidity. As the dew point temperature, at the apparatus is always necessarily maintained considerably below the room temperature, there is ample available refrigerating effect to maintain a lower temperature in.the room than outside in summer, and to absorb the heating efiect from. machinery or other sources of heat in the room. This permits practically the same temperature to be maintained in summer as in winter. y

In the accompanying drawings, consisting of two sheets: Figure 1 is a diagrammatic plan view, partly in section, of an apparatus embodying the invention for controlling the humidity and temperature of air in. the rooms of a building. Fig. 2 is a fragmentary longitudinal sectional elevation of the air trunk and means for operating the dampers thereof. Fig. 3 is a sectional plan thereof. Fig. 4 is a plan view, partly in section, on an enlarged scale, of the valves controlling the flow of water used for humidifying the air. Fig. 5 is a sectional ele- -vation' of the operating means for the damper which controls the admission of air to the humidifier.

Like letters of reference refer to like parts in the several figures.

A represents a building or otherinclosure having different rooms or apartments aa a? which are to be supplied with air and the humidity and temperature of which are to be individually controlled; B an air trunk. or

passage having admission openings] 5 respectively for externaltair and air returned from one or more rooms of the building; C a fan or device for causing air to flow through the trunk and into the rooms through-sepa-' rate passages or flues c c c in the air trunk; D humidifying devices for saturating the air in the humidifying chamber (1 of the air trunk with moisture; and E means for eliminating the free water, together with the solid impurities, from the air.

The humidifying devices preferably consist of numerous spray nozzles ofthe cyclone type which discharge water under pressure in the form of a ve y fine spray or mist so as obtained.

to thoroughly saturate the air in the humidifying chamber with moisture. The eliminator preferably consists of a series of zig-zag plates arranged vertically and spaced apart to form numerous zig-zag' passageways between them for the air. The saturated air impinges against the oblique faces of the eliminator plates, and the free water together with the mpurities from the air collect on the plates and flow down them into a collecting well in the bottom of the humidifier. A flushing tank F is also shown over the eliminator plates provided in its bottom with slots through which the water flows down between the eliminator plates for more thoroughly wetting their surfaces.

G represents a low pressure centrifugal pump which takes the water from the well in the humidifier and supplies it by pipes g g and g respectively to the flushing tank F, to a water heater H, and to a water cooler I; and G represents a high pressure pump which takes. the water from-the heater and cooler by pipes g and g and supplies it by a g and 9 Between t e heater and cooler to permit the water to circulate without passing through either the heater or the cooler. By these' means the same water with suchiad- .dition of fresh water as may be required to make up for that assimilated by the air, can be repeatedly circulated, being taken from the collecting well of the humidifier and returned to the spray nozzles after more or less of it passes either through the heater, the cooler or the by-pass, depending upon the required temperature of the water delivered to the humidifying nozzles.

9 represents a strainer for removing impurities from the water supplied to the humidifyin nozzles. r

If pre erred, fresh water can be supplied to the humidifying nozzles and the soiled water drained off from the eliminator.

The air humidifying and drying means means constructed as. described have proven very eflicient in practice and are therefore.

preferred, but the controlling means of the system, about to be described, are not 'dependent upon these particular means and any vsuitable means can be employed for these purposes. 1 Y

K represents an ordinary thermostat lo- 'cated in the discharge end of the humidifier or in any other suitable place where it will be subjected to the temperaturebf'the saturated air leaving the humidifier, for maintaining a constant temperature of the dew point or saturated air in the humidifier. For this purpose'the thermostat K in the system illustrated controls a valve L, Fig. 1, which regulates the s uppl of steam to the water heater, and also a t ree-way valve or 130 vice M regulating the flow of water 1 the temperature of the spray water. The rmostat also controls a damper N 1ich regulates the proportions of external and return air from the building; ad-

tted to the humidifier by more or less ening one and closing the other of the air mission openings 3) Z). These valves and damper are actuated by diaphragms or tors Z, m and n, respectively, of Well own construction operated by compressed r supplied from a reservoir n, or other urce of supply, through suitable pipes at d n controlled by the thermostat K. This ermostat, under the influence of the temrature of the saturated air in the humidir, operates through the conjoint action. of e steam supply valve L the three-way lve M and the damper N to keep the satuted air'in the humidifier at a predeter- '.ned fixed temperature. The air fromthe midiiier being saturated with water at a astant temperature, its moisture contents main constant, that is, the air contains alliys the same number of grains of moisture r cubic foot, ano the relative humidity of e air in the room or rooms to which this turated air is admitted Will therefore dend upon the temperature in said room or actuating devices Z, m and n for the ll and M and damper N are adjustso that when thetemp erature of the exnal air rises to a predetermined degree e valve lb will completely shut off the am from the water heater and the damr N will close the admission opening 1' return air, whereby only unheated wa and external air Will be used in the unidifier, the cooler and by-pass being ndered inoperative at this time by means reinai'ter described, and the temperature the dew point in the humidifier becomes at of the wet bulb ten'lperature ot' the ere 'nal air entering the humidifier. This due to toe fact that saturation occurs thout addition of heat to the air or water a temperature which is the same as the t bulb temperature of the external air. the wet bulb temp rature of the external nosphere exceeds the temperature or the w point in the humidifier for which the ermostat K is adjusted, then it becomes ,cessary to dehumidify or extract moisture om the air admitted to the humidifier. 11' this purpose a thermostat O is employed ich is influenced by the wet bulb temperare of the external atmosphere and controls three-Way valve P, or other device, for connecting the supply pump for the ray nozzles from the heater and connectg it to the cooler so that only refrigerated ter will be supplied to the huinidifying lzzles D. This three-Way valve or device rough the by-pass pipe 9, to thereby govclose the admission opening e for enter inoiflse T is actuated by a diaphragm or motor ,1) which can be operated by compressed air controlled by the thern'iostat U as in the case of the other three-way valve M. The thermostat U is adjusted so that it is normally inactive, but when the wet bulb temperature of the external. atmosphe'e equals the temperature of the dew point for \VlllCll. the other thermostat K is adjusted, it goes into action and causes the three-way valve to move to the position shown in Fl 4;, in which it closes the pipe g from heater and opens the pipe 9 trom the cooler. Only cool or reirige ed water will then be supplied to the spit ,7 nozzles and the tem perature of this "will be regulated as required to maintain the predetermined temperature of the dei v point in the humi tier by the valv h which, under the action the thermostat controls the proportions or water taken from the cooler the lay-pass. refrigerated Water will chill the air enter the humidifier and cause a precipitation of its moisture, or the formation of dew, whereby a portion. of the moisture contents the will be extracted or its abso We humidity lowered, The wet bulb thermostat also preferably controls an air-operator. device ((2, Figs. 1 and 5, by which the damper N is cause air when the wet bulb temperature oferternal air exceeds temperature of the dew point in the humidifier, so that only 1eopens an inlet port if and closes an exhaust port g in its casing, Air can then pass the valve to the damper actuating motor a. l Vhcn, however, the thermostat operates to shut off the water heater, air is admitted to the diaphragm Q by a pipe and the valve (1 is shifted to close the inlet port g and open the exhaust port which permits the air to escape from the dampereactuating motor 91 and the damper will be moved to close the external air admission opening I) by a spring y shown by dotted lines in Fig. 5, or other means. If desired, the automatic thermostat U and the means operated thereby could be omitted and the cold Water turned on manually when the external atmospheric conditions make it necessary to de-humidi'fy the air.

The water in the cooler is kept between the predetermined maximum and minimum temperatures requisite for dehumidifying the air as explained, by an ordinary refrigerating plant comprising ammonia circulatagain rises to the maximum degree.

ing pipes R, a supply tank r a condenser r, and a compressor 1' operz'xte by a motor 7*. This refrigerating plant can be controlled manually but is preferably controlled automatically by maximum and minimum temperature thermostats s 8 located in the cooler and operating a suitable valve 8 in the circulating system and also a controller a for the motor through suitable air-operated motors or devices, such as previously described. When the temperature of the water rises to the predetermined maximum degree, the thermostat is operates to start the motor andco'mpressor and open the valve 8 and the refrigerating means operate to lower the temperature of the water to the predetermined minimum degree, when the other thermostat s operates to stop the motor and compressor and close the valve 8 The refrigerating plant then remains inactive until the temperature of the Water Any other suitable means, whether automatic or not, could be employed for keeping the water in the cooler at a suitable temperature.

For independently regulating the temperature and relative humidity in the rooms of the building, the fines a a a leading to the several rooms connect with the air trunk B by branch hot and cold air passages T T controlled by dampers t t, respectively, and a steam radiator or other air heater T is placed in the hot air branch passage T. The dampers t t for each of the fines c c c are connected so that as one opens the other closes, thus permitting a mixture of any desired proportions of hot and cold air to be delivered to each room. The dampers for the several fines are separately actuated by air-operated motors or devices :5 controlled by hygrostats U U U located in the several rooms. Hygrostats, such as disclosed in Patent No. 896,690, granted August 18. 1908, to myself, assignor to the Buffalo Forge Company, which have differentially acting elements influenced by the wet and dry bulb temperatures of the rooms, are preferably employed. Each hygrostat operates through the motor t and dampers controlled thereby to regulate the proportions of hot and cold air delivered to the room in which it is located and thereby consequently governs the temperature and relative humidity in such room, so that the atmospheric conditions of the several rooms are independently controlled. Any other suitable means controlled by the hygrostatscould be used for regulating the temperature of the air del1v ered to the rooms, or the humidistats could control the room temperatures by governing separate sources of heat for the rooms, or in any other suitable way.

V represents an exhaust pipe havlng branches connecting the thermostat 0 an the several hygrostats U U U with the fan C for creating a circulation of air past these instruments to insure the proper action thereof. v

It has not been attempted in this application to describe or illustrate in detail the construction of the various instruments and devices employed in the system, as the invention does not relate to the same, and any devices capable of performing the functions stated could be employed.

I claim as my invention:

1. The combinationtof humidifying means for saturating air with water, means a for heating the Water to add moisture to the air when the wet bulb temperature of the air i being treated is below a predetermined temperature of the saturated air, means for cooling the water to condense moisture from the air when the wet bulb temperature of the air being treated is above said predetermined temperature of the saturated air, and automatic means for controlling the said heating and cooling means to maintain said predetermined temperature of the saturated air, substantially as set forth.

2. In a system for controlling the humidity of air, means for saturating the air with moisture at a predetermined substantially 4 constant temperature, including means for raising the temperature of the water 1n the humidifier above said constant temperature of the saturated air for adding moisture to water supplied to the air for dehumidifying the air when the wet bulb temperature of u the air admitted to the humidifier exceeds said constant temperature of the humidified air, substantially as set forth.

4. The combination of a humidifier for air,.automatic means influenced by the humidified air for maintaining a predetermined substantially constant saturation temperature of said humidified air, and automatic means governed by the Wet bulb temperature of the air admitted to said humidifier and acting when such temperature exceeds a predetermined degree to dehumidify the air admitted to the humidifying means, substantially as set forth.

, 5; The combination of a humidifier for air, automatic means influenced by the humidified air for regulating the temperature of the humidifying water to normally maintain a predetermined substantiall constant saturation temperature of i said umidified sir and udditionzil sutomu-tic niesns' gov 3 erned by the air admitted to said humidity 1 air, automatic means influenced by the lin 1 in the humidifier to normally maintain ing meensu/hich are normally inactive and operate upon a predetermined Wet bulb temperature of the air admitted to the humidi- I fier to lower the temperature of the humiditying water, substantially as set forth 6. The combination of u humidifier nlidiiied air for the tempeiut predetermined substantially constraint setu 1 tion temperuture of the humidified air additional 9 "tcmetic P ns governed by wet bulb to or :he air edmitte 1 said humidii or which normally inactive and operate upon at s i temperature of the u niidifier to lower the te oerutnre of the uter, substun iully us set lei ibinution of u humidifier "2 means influenced bythel r regulating the temperet -ying Water to normally in etermined substantially .tion tern means :or

nil" uutoror midiiied ai of the hun train :1 stunt sut lilltllllQd 221 K 1 humidifyi refrigerating Water, and udditionul e rustic met governed by the Wet bulb A peruture o the admitted to suid humiditier WillCll are normally inactive and j operate EPFE a predetermined wet bulb tern- 'ieruture the air admitted to the humid Iitier to renoer Weter heating means in active and said re rigeruting meuns active,

substantially as set forth.

The combinuton a humidifier for sir, means influe ced the humidified air acting auto uticslly when the Wet bulb temperuture of the air admitted to the hum.

tier is below at predetermined degree to jinsintuin a predetermined substantially constant suturution temperature of the hu-- iniditied air and means governed by the Wet bulb temperature oi the sir admitted to the f humidifier which are normally inuctive operate uutomaticully When the Wet'bulb to tncrut e of the udinitted to the l nsidifier exceeds predetermined degree to lower the temperature of the uir in the humidifier to dehumidily it, substuntiully es set forth,

j 9. The combination of means for delivlcring' air to an inclosure, u humidifier for the air, automatic means influenced by the humidified sir for regulating the temperature of the humiditying Water and admitting" external air and return air from suid inclosure in diderent proportions to said humidifier to normally maintain u predetermined substantially constant saturation temperature of the humidified sir and means governed by the Wet bulb tempersture of the external air which ere normally inactive and operate uutomuticelly when the :und relative humidity in. the sev substantially set forth "Wet bulb temperature of the externsl air tor inuintuinin u substuntiully constant saturation temperature thereof, means for so er-etc coi'ireying the humidified air to means for heating no lied sir end oyerned by t .1 f the control g end unheated uir d red t 1 independently the u oorti on a The combination o' n euns influenced by uintuini sub 1 suture r conveying m cneniizin u re,

p e the ..ii'

s and 2 itre ntinl erne-t y L sul in said inclosur from s I inclosure to re 'ulute the t utive l mid' of u t itiully set f 12., The cor binutio for time if With ioi raisin e temnerutr her to moisture to cur W i bulb temperature of the bet is below a predetermined tempermre saturated air, cooling moons for lowering the temperature in the humidifier condense moisture from air when the Wet bulb temperature of t e sir b-ei is above said predetermined temper the saturated air, and automatic menus for controlling said heating end coolin means to maintain said predetermined "uture oi the saturated uir, substantiuily us set forth 13. The combination of an air humidifier, bestug means and cooling" means for ultering-the temperuture in the humidifier, sutomutic meuns influenced by the humidified sir controlling said heating menus or said cooling means to maintain u predetermined substantially constant saturation llGDL peruture of the humidified sir, end eddit-ionel automatic means which are normally inactive and operate upon a predetermined Wet bulb temperature of the air admitted to the humidifier to transfer the control of said controlling means trom'suid heating means to said cooling means, substuntiully us set forth.

i l. The combination of u humidifier for air, means influenced b the humidified air .for maintaining a su stantially constant -a hygrostat governed by the hygrometric condition of the air in the inclosure, and instrumentalities controlled by said hygrostat for controlling the temperature of the humidified air delivered to the inolosure to regulate the humidity in the inclosure, substantially as set forth.

15. lhe combination of a humidifier for air, means influenced by the humidified air for maintaining a substantially constant saturation temperature thereof, means for conveying the humidified air to an inclosure, a differential hygrostat governed by the Wet and dry bulb temperatures-of the air in the inclosure, and instrumentalities controlled by said hygrostat for controlling the temperature of the humidified air delivered to the inclosure to regulate the humidity in the inclosure, substantially as set forth.

16. The combination of a humidifier for air, means influenced by the humidified air for maintaining a substantially constant saturation temperature thereof, means for conveying. the humidified air to separate rooms, hygrostats governed by the hygrometric conditions in the several rooms, and instrumentalities controlled by. said hygrostats for separately controlling the temperature of the humidified air delivered to each room to independently regulate the humidity in the several rooms, substantially as set forth. V

Witness my hand, this 6th day of April,

WILLIS H. CARRIER. Witnesses C. W. PARKER, C. B. HoRNBEoK. 

